Improvement in compound steam-engines



2 Sheets-Sheet l. L. HUN-BOON.

COMPOUND. STEAM-ENGINE.

Patented Sept.l2, 187.6.

,Jjw T/A;

N PETERS. PHOTO LITHOGRk tail, enlarged in section.

UNITED STATES PATENT OFFICE.

LAFAYETTE HUNTOON, 0F NATIOK, MASSACHUSETTS;

-IMPROVEMENT l N. COMPOUND STEAM-ENGINES.

Specification forming part of Letters Patent No. 182,196, dated September 12, 1876; application filed May 10, 1876.

' of N atick, in the county of Middlesex and State of Massachusetts, have invented certain Improvements in Compound Steam-Engines, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, making a part of this specification, in which- Figure lisaperspective view of a compoun engine constructed in accordance with my invention. Fig. 2 is a horizontal section through the center of the same. Fig. 3 is a transverse vertical section through the same. Fig. etisa section on the line at w of Fig. 2; Fig. 5, de-

My presentinvention relates to that class of compound engines having an outer cylinder provided with an inner movable piston-cylinder traversing on a stationary piston, the steam first acting between the stationary piston and i the inner end ofthe movable piston'cylinder,

and afterward expansively between the outer end of the piston-cylinder and the end ot the outer cylinder; and' my invention consists in certain details of construction, as hereinafter set forth and specifically claimed.

To enable others skilled in the art to no and are providedwith packing-rings, so as to move therein withontleakageof steam. Within the piston-cylinder B is a stationary piston, G, on which it moves, the rod D, which supports the piston G, passing steam-tight through the head of the cylinder B, and being secured to the center of the head of the cylinder A. To the piston-cylinder B is secured the pistonrod E, which passes through thehead of the cylinder A, andis attached to the cross-head F, which slides in guides k. G is'the connecting-rod, secured to the crank H on the driving-shat't I. c is an opening in the top of the outer cylinder A, through which steam is admitted into the annular Space dbetween the cylinders A B, in which space the steam is confined between the heads aa of the piston-cylinder. K is a hollow tubular valve, which slides steamtight through the heads a a/ and projections c e on the inner sides thereof.

The tubular valve K isprovided at or near its center with a series of apertures, f, which are exposed between the projections e e to allow the steam in the annular space at to enter the tubular valve K, near each end of which are formed one or more ports, g, which communicate with the ports it" of the piston-cylinder B, when the valve K is moved into the desired positions. These ports t' t" are alternately opened and closed by the sliding of the valve K, the stem L of which passes through the head of the cylinder A, and is jointed at its outer end to a connecting-rod, M, which is pivoted to a crank, it, secured to the end of the crank-pin lot the crank H, and by the connections-above described the tubular valve is made to move simultaneously with and at the same speed as the piston-cylinder during aportion of its stroke but when. it has nearly completed its stroke in either direction the valve K receives a sudden movement independently of the piston-cylinder, whereby the .steam is admitted at one end ofthe pistoncylinder, and at the same time cutoff from the other end. On one side of the cross-head F is a projection, N, over which fits a bifurcated slide, P, securcdto the stem L of the valve K, a guide being thus t'ormed to support the stem and insure its being moved in'a straight line.

To allow the valve to have aslight movement independently of its stem, so that it may at all times bear uniformlyon its seat in the event however, abuts against the valve when it is pushed by its stem, and the steam is prevented from escaping through the aperture at the joint by a tight head, g. In line with each port i i, and within the seat of the valve K, a

is formed a groove, 16, extending entirely around the valve, which is constantly filled with steam, which exerts a uniform pressure on and serves to balance the valve. 1" s are the exhaust-ports of the outer cylinder A, located at each end thereof and communicating with an exhaust-pipe, Q, provided with a pair of hollow valves, R S, secured to a rod, T, which passes out of the exhaust-pipe through a stuffing-box, and is jointed to a rod, U, connected with an eccentricfV, on the drivingshaft 1, by which the desired movements are imparted to the valves R S, to alternately open and close the exhaust-ports r 8.

Within the pipe Q, in line with the ports 1" s, are formed grooves 15 extending entirely around the valves R S, whereby they are balanced by the equal pressure of the steam thereon. W- is an outlet in the pipe Q, for the escape of the exhaust steam.

The parts being in the position seen in Fig. 2, the steam admitted into the annular space 0i, through the opening 0, enters the valve K through the apertures f, and thence passes to the port 0), through the portsg adjacent thereto, into the piston-cylinder, between its head a/ and the stationary piston O, wherebythe piston-cylinder is made to move through the outer cylinder A in the direction of the arrow, the steam in the piston-cylinder on the other side of the piston G escaping through the port 1" and space or opening 12 around the stem L, into the outer cylinder A, between its head 13 and the head a of the piston-cylinder B, the steam working expansively, and assisting in driving the piston-cylinder in the direction in which it is already moving, the amount of pressure exerted being in proportion to the difl'erence of the areas of the stationary piston O and the outer surface of the head a ofpleted its stroke, the valve K commences to move in the opposite direction,- cutting off communication between the port 2" and the opening 12 into the cylinder A, simultaneously with which the portal and ports 9 adjacent thereto are brought into line with, each other, allowing a fresh supply of steam to enter the piston-cylinder between its head a and the piston G, to force the piston-cylinder in the direction contrary to the arrow. This same movement of the valve uncovers the port 0', and allows the steam first introduced between the piston G and head a to pass out of an opening, 15, similar to that 12, into the outer cylinder A, between its head 14 and the head a of the piston cylinder, where it works expansively-to assist in forcing the piston-cylinder, as previously described. When the piston-cylinder is moving in this direction, the steam between its head a and the head 13 of the outer cylinder A is exhausted through the port 4", into the adjacent end of the pipe Q, and thence through the hollow valve It to the discharge-outlet W, this valve being in a position to leave the port 1' uncovered.

Just before the arrival of the piston-cylinder at theend of its stroke in this direction the valve K is again moved, cutting off communication between the opening 15 and port i, and at the same time bringing the ports g of the valve in line therewith, and also opening communication between the port 1; and the opening 12, when the parts are brought to their original position, (seen in Fig. 2,) and the operation continues as before.

By admitting the steam into the space between the outer cylinder and piston-cylinder, and locating the valve K, exhaust-pipe Q, and its valves HS in the positions shown, the construction is rendered less complex, the cost reduced, and convenient access afforded for repairs.

The outer end of the crank it is so placedthat it will travel in the same circle as the end of the main crank H, or rather the crank-pin t. This arrangement gives the valve the exact motion necessary to open and shut the ports at the requiredtimes,

What I claim as my invention, and desire to secure by Letters'Patent, is

1. The sliding tubular valve K, with its apertures f and ports g, placed within the side of the piston-cylinder B, in combination with the ports M and openings 12 15, operating sub stantially in the manner and for the purpose described.

2. In a compound 'engine,'th e valve-crank arranged to travel in the same circle with, and slightly in advance of, the main crankH, in combination with the rods M L, piston B, and guide N P, substantially as and for the purpose set forth.

Witness my hand this 2d day of May, A. D.

LAFAYETTE HUN TOON In presence of- N. WJ'STEARNS, B. E. TEsoHEMAoHER, 

